High-Tech Help for Optimizing Total Knee Outcomes

“With traditional knee replacements, patients usually need to get a CT or MRI prior to the procedure to get the mapping done ahead of time,” says Ms. Denham. “We still do some preoperative mapping with an X-ray just to give us an idea of implant sizing, but as soon as the patient is positioned and everything is a go, the surgeon will place the robot’s handpiece at specific landmarks on the leg, which gives the robot live imaging. It uses those landmark trackers to gather all the anatomical data, and then it shows the estimated size of the implant.

“All of it is basic, and it happens so quickly,” adds Ms. Denham. “It’s amazing. The precision is incredible as well. Our patient outcomes and their recovery times are so much better now. They’re bouncing back, returning to their usual activities and getting back to work. Their pain is less after surgery because they get such a precise fit with the prosthesis.” North Valley surgeons use the robot vendor’s wide selection of implants, which they say provide a more natural fit thanks to the robot’s planning assistance.

Her surgeons are investigating another new feature with the robot: The ability to analyze data the robot collects to identify and optimize surgical techniques and patient outcomes. Another cool aspect of the new robot: a small footprint. “It’s not a large device that looks like a tank,” says Ms. Denham. “In fact, it can literally be put into a small suitcase and transported anywhere. If we ever needed to bring it to another facility or move it somewhere else inside our facility, it’s nothing.”

Although cost has been a hurdle for many orthopedic ASCs evaluating robots, Ms. Denham says that after four years and two robots, they have been a boon for her facility. “There definitely is the initial capital cost for the facility, but that all comes back,” she says. “It is most certainly worth the investment. Anything that’s going to improve patient outcomes, get a better fit of the prosthesis, be beneficial for the patients — it’s definitely sought after and they’re interested.

“All of our patients are really engaged and taking personal responsibility for their health,” she says. “Most of the time, they’ve been out of commission for a while, haven’t been able to work or live their life. When they’re told about the robot and the potential for less downtime, who can say no to that?”

Last October, Fred Cushner, MD and Peter Sculco, MD, orthopedic surgeons at Hospital for Special Surgery (HSS) in New York City, performed the first knee replacement with a “smart” implant that collects and transmits data, enabling them to monitor their patients’ recoveries from anywhere through a cloud-based digital dashboard.

Thanks to its embedded sensor, the implant can track steps taken, walking speed, range of motion and other indicators for days, weeks, months, years and potentially decades postoperatively, with the surgeon able to access and analyze the data at their convenience. This remote patient monitoring is poised to be the next horizon in knee replacement recovery, and can be especially useful in the immediate weeks after surgery when the patient is working hard to rehab.

The implant was granted De Novo classification and authorization from the FDA last August, and Dr. Cushner has been involved in its development from the beginning, coming up with the idea on a napkin in 2014. “The idea was, if this implant is a piece of metal, why can’t we get more information from it?” he says. As opposed to wearable tracking devices that patients may not use properly or at all during their recoveries, the smart implant has no patient compliance issues. “That’s why we decided to make the sensor internal and build it into the prosthesis,” he says.

The execution is similar to that of a pacemaker, with the sensor battery-operated. It collects data every day during the first year following surgery, providing information on how the knee is functioning. The monitoring can continue for much longer, as the battery can last at least a decade. The data the implant records is transmitted to a personal base station in the patient’s home via Wi-Fi and securely uploaded to a cloud-based platform that the surgeon can access and review.

The benefits of remote monitoring are obvious — fewer postoperative office visits, objective data available on demand and a potentially stronger provider-patient relationship during rehab. “I can log into the dashboard, look at my patients and see how they’re doing,” says Dr. Cushner, who usually checks on patients’ progress once a week. “I can look at the trends — how they’ve been doing for the last week and compare it to previous weeks. I can look at the data and see if I can pick up any problems that need to be addressed.”

Dr. Cushner says the smart implant can improve upon telehealth, which he calls very subjective when assessing total knee patients postoperatively. He envisions being able to tell a patient to bend their knee in their home and see the amount of flex in real time on the cloud-based dashboard. “With the smart implant, we can actually get to the point,” he says.

Another feature under development is the ability to turn the implant “on” during an office visit for real-time functional evaluations. “We’ll have patients squat, pivot or walk down stairs, and look at that data as it is generated — in addition to looking at the daily data patterns it collects,” says Dr. Cushner.

The idea is to identify patients who may not be progressing as well as they should as early as possible. Armed with relevant information, the surgeon can alter the patient’s physical therapy plan or pain management regimen.

Smart implants could eventually produce value for the entire specialty, as researchers can analyze gait metrics and other data from large cohorts of patients and translate it into evidence-based recommendations to improve outcomes. “By analyzing that data, we’ll get gait patterns of satisfied patients and unsatisfied patients, and be able to intervene earlier rather than wait for patients to need a revision or a more costly procedure,” says Dr. Cushner. “There may even be telltale signs, such as the gait pattern of an infected knee, that we’ll be able to pick up before revision is needed rather than when it’s a full-blown infection in the prosthesis, which then has to be removed.”

Smart implants have already generated more than 20 million data points, according to Dr. Cushner. “When you go to an orthopedic meeting, surgeons argue about the best way to put in the knee implant, the best alignment, and there’s no real consensus,” he says. “There’s so much that is unanswered. I think what we’re going to see is that the answer is not the same for everybody. A short, stocky person might have a different post-op goal than somebody who’s six-foot-seven and lean. We will be able to answer these unanswered questions once we have the ability to look at the big data.”

Dr. Cushner is involved in the development of a single-use, handheld smart tool that provides individualized alignment data for a patient’s implant without requiring preoperative imaging. “As much as doctors feel they’re very accurate, they’re not as good as they are when using a smart instrument,” he says. “The benefit of this device is that it’s compact, there’s not a big capital expense and it’s much more accurate than traditional instruments. It now also has a sensor that enables you to balance the soft tissue and then perform your cuts for a more aligned and well-balanced knee.”

Many surgeons are loathe to change their time-honored practices, but Dr. Cushner feels better equipped using these cutting-edge technologies. “They make you more efficient in the OR,” he says. “Almost every major implant company is doing something with digital health. It’s becoming the norm, not the novelty.” OSM